نتایج جستجو برای: titania phase
تعداد نتایج: 602176 فیلتر نتایج به سال:
A series of V205/TiO 2/SiO 2 catalysts were structurally investigated by in situ Raman spectroscopy and chemically probed by methanol oxidation in order to determine the molecular structure-reactivity relationships of the V205/TiO 2/SiO 2 catalysts. Only surface TiO,. species are present on the 3% TiO 2 /S iO 2 catalysts, and the surface TiO x species as well as bulk TiO 2 (anatase) particles c...
The driving force for coarsening is provided by the excess interfacial free energy. In a system with isotropic interface energies, classical coarsening theories can predict the evolution of the sizes of spherical crystals. However, if the interfaces are anisotropic, crystal growth and shrinkage may be limited by the surface attachment/detachment rate, the motion of ledges, or the nucleation of ...
We describe the use of benzyl alcohols in a solvothermal/alcoholysis reaction to form nanocrystalline sheets of anatase titania. By tuning the reaction conditions, we adjust the size of the nanosheets. The type and density of benzyl groups that decorate the basal plane of the titania sheets control the self-assembly into layered structures. These layered materials can be grown from solid substr...
Well-defined, ordered arrays of nanoscale depressions were obtained in linear-brush-type polystyrene-block-polycarbosilane (PS-b-PCS) diblock copolymer thin films by acetone vapor annealing and silica nanodot arrays were directly obtained from such thin films deposited on a titania substrate by one-step exposure to UV light as a result of transformation of the PCS units to silica, driven by the...
A visible light triggered protein delivery system has been assembled through hydroxyl coordinated onto titania nanoparticles. Biomolecules such as hemoglobin (Hb) can be controlled-released from the hybrid material TiO(2)-DB-Hb by switching visible light on/off. The released Hb not only retains its senior structure but also can fulfil the enzymatic bioactivity. Controlled delivery of Hb stems f...
Research on homogeneous and heterogeneous catalysis is indeed convergent and finds subnanometric particles to be at the heart of catalytically active species. Here, monodisperse gold clusters are deposited from the gas phase onto porous titania generating well-defined model systems and the resulting composite materials exhibit a sharp size-dependency on the number of gold atoms per cluster and ...
In this study, characterization of vanadia supported on Al-modified titania nanotubes (TiNTs) synthesized by the alkaline hydrothermal treatment of TiO2 powders has been reported. A promising catalyst for oxidative dehydrogenation (ODH) of propane was prepared via the incipient wetness impregnation method. The morphology and crystalline structure of TiNTs were characterized by transmission elec...
Titania, single-doped and lanthanum-silver co-doped titania nanocomposite were coated on cellulosic and polyacrylonitrile fibers via sol–gel method. The prepared samples were evaluated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photolumines...
We report a spontaneous phase transformation of titania nanotubes induced by water at room temperature, which enables the as-anodized amorphous nanotubes to be crystallized into anatase mesoporous nanowires without any other post-treatments. These mesoporous TiO(2) nanomaterials have a markedly improved surface area, about 5.5 times than that of the as-anodized TiO(2) nanotubes, resulting in a ...
We use in situ X-ray absorption and diffraction studies to directly monitor the crystallization of different titania polymorphs in one and the same solution. We find that, despite the commonly accepted polymorphic-crossover from anatase to rutile triggered by the critical size of nanoparticles, in the solution their respective nucleation and growth are independent processes. Moreover, we find t...
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